Patricia Leung

Randomized Controlled Trial Comparing Adaptive-support Ventilation with Pressure-regulated Volume-controlled Ventilation with Automode in Weaning Patients after Cardiac Surgery

Background:Adaptive-support ventilation (ASV) is a minute ventilation–controlled mode governed by a closed-loop algorithm. With ASV, tidal volume and respiratory rate are automatically adjusted to minimize work of breathing. Studies indicate that ventilation in ASV enables more rapid weaning. The authors conducted a randomized controlled trial to determine whether ventilation in ASV results in a shorter time to extubation than pressure-regulated volume-controlled ventilation with automode (PRVCa) after cardiac surgery. Methods:Fifty patients were randomly assigned to ASV or PRVCa after elective coronary artery bypass grafting. Respiratory weaning progressed through three phases: phase 1 (controlled ventilation), phase 2 (assisted ventilation), and phase 3 (T-piece trial), followed by extubation. The primary outcome was duration of intubation (sum of phases 1–3). Secondary outcomes were duration of mechanical ventilation (sum of phases 1 and 2), number of arterial blood gas samples, and manual ventilator setting changes made before extubation. Results:Forty-eight patients completed the study. The median duration of intubation was significantly shorter in the ASV group than in the PRVCa group (300 [205–365] vs. 540 [462–580] min; P < 0.05). This difference was due to a reduction in the duration of mechanical ventilation (165 [120–195] vs. 480 [360–510] min; P < 0.05). There were no significant differences between the ASV and PRVCa groups in the number of arterial blood gas samples taken or manual ventilator setting changes made. Conclusions:ASV is associated with earlier extubation, without an increase in clinician intervention, when compared with PRVCa in patients undergoing uncomplicated cardiac surgery.

Attitudes towards ethical problems in critical care medicine: the Chinese perspective

IntroductionCritical care doctors are frequently faced with clinical problems that have important ethical and moral dimensions. While Western attitudes and practice are well documented, little is known of the attitudes or practice of Chinese critical care doctors.MethodsAn anonymous, written, structured questionnaire survey was translated from previously reported ethical surveys used in Europe and Hong Kong. A snowball method was used to identify 534 potential participants from 21 regions in China.ResultsA total of 315 (59%) valid responses were analysed. Most respondents (66%) reported that admission to an intensive care unit (ICU) was commonly limited by bed availability, but most (63%) would admit patients with a poor prognosis to ICU. Only 19% of respondents gave complete information to patients and family, with most providing individually adjusted information, based on prognosis and the recipient’s educational level. Only 28% disclosed all details of an iatrogenic incident, despite 62% stating that they should. The use of do not resuscitate orders or limitation of life-sustaining therapy in terminally ill patients reported as uncommon and according to comparable reports, both are more common practice in Hong Kong or Europe. In contrast to European practices, doctors were more acquiescent to families in decision-making at the end of life.ConclusionsA number of differences in ethical attitudes and related behaviour between Chinese, Hong Kong and European ICU doctors were documented. A likely explanation is differing cultural background, and doctors should be aware of likely expectations when treating patients from a different culture.

The Adsorption of Vancomycin by Polyacrylonitrile, Polyamide, and Polysulfone Hemofilters

The aim of this study was to characterize vancomycin adsorption by polyacrylonitrile (PAN), polyamide, and polysulfone hemofilters using an in vitro model of hemofiltration. Vancomycin (36 mg) was added to a blood-crystalloid mixture of known volume (target concentration of 50 mg/L) and pumped around a closed circuit. Adsorption, which was calculated from the fall in concentration over 120 min, was significantly greater by 0.6-m(2) PAN filters (10.08 +/- 2.26 mg) than by 0.6-m(2) polyamide (5.20 +/- 1.82 mg) or 0.7-m(2) polysulfone (4.80 +/- 2.40 mg) filters (P < 0.05). Cumulative adsorption was not changed by the addition of 500-mL lactated Ringers solution (to reduce the circulating vancomycin concentration). These data show that although adsorption of vancomycin by PAN, polyamide, and polysulfone hemofilters occurs, the absolute adsorption is small. Adsorption is dependent on filter material and is not reversed by a decrease in circulating concentration.

Patient and family satisfaction levels in the intensive care unit after elective cardiac surgery: study protocol for a randomised controlled trial of a preoperative patient education intervention.

Introduction Patients and their families are understandably anxious about the risk of complications and unfamiliar experiences following cardiac surgery. Providing information about postoperative care in the intensive care unit (ICU) to patients and families may lead to lower anxiety levels, and increased satisfaction with healthcare. The objectives of this study are to evaluate the effectiveness of preoperative patient education provided for patients undergoing elective cardiac surgery. Methods and analysis 100 patients undergoing elective coronary artery bypass graft, with or without valve replacement surgery, will be recruited into a 2-group, parallel, superiority, double-blinded randomised controlled trial. Participants will be randomised to either preoperative patient education comprising of a video and ICU tour with standard care (intervention) or standard education (control). The primary outcome measures are the satisfaction levels of patients and family members with ICU care and decision-making in the ICU. The secondary outcome measures are patient anxiety and depression levels before and after surgery. Ethics and dissemination Ethical approval has been obtained from the Joint Chinese University of Hong Kong—New Territories East Cluster Clinical Research Ethics Committee (reference number CREC 2015.308). The findings will be presented at conferences and published in peer-reviewed journals. Study participants will receive a 1-page plain language summary of results. Trial registration number ChiCTR-IOR-15006971.